The present invention relates to communication processing apparatuses that store communication data in buffers, image forming apparatuses, and methods of communication processing.
In a network communication processing device, a communication processing circuit stores received data in buffers through the use of direct memory access (DMA). When network data blocks are received, they are sequentially stored in the buffers. Management information for such buffers is held in descriptors that are provided in correspondence with the buffers. Buffers in which received data is to be stored are sequentially identified by referring to each corresponding descriptor.
In cases where descriptors are used as described above, the configuration of the descriptors needs to be changed when the configuration of the buffers is changed. However, when data blocks are received from a network during a period of processing for changing the descriptors, it is not clear whether or not the data has been properly buffered and, consequently, the integrity of the data content may not be accurate.
For instance, referring to FIG. 5A, in examples in which buffers are provided in a random access memory (RAM)—memory external to the communication processing circuit—and the power supply of the RAM is switched off in accordance with the power supply mode of the device, buffers used by the communication processing circuit may be switched from the buffers in the RAM to buffers in an internal memory that continues to be supplied with power, as illustrated in FIG. 5B. In such an example, received data may be lost during the switching process due to changes in the descriptors.